Introduction

The Tamron AF 24-135mm f/3.5-5.6 SP AD Aspherical (IF) was a very popular lens during
the film era targeting especially travel and outdoor photography. There were frequent
discussions whether to prefer the Canon EF 28-135mm f/3.5-5.6 USM IS because of image
stabilization or this Tamron lens due to its extra kick at the wide end of the zoom
range and possibly a higher image quality. Well, the film era is over and the Canon
zoom isn't all that useful anymore on APS-C DSLRs with a 45mm equivalent at the wide
end of the zoom range. The Tamron isn't stellar in this respect either but with its
38-216mm full frame equivalent can still be used for mainstream applications but
there're some question marks regarding its former strength in landscape photography.
The lens is available in all major mounts except Four-Thirds.

The optical construction is made of 14 elements in 10 groups including four (!)
hybrid asphericals and one AD (Anomalous Dispersion) element.
The aperture mechanism features 7 aperture blades. It has a size of 81x79mm and
a weight of 530g so it can still be considered as quite compact.
The minimal focus distance is 0.4m resulting with a max. magnification
of 1:3.3 at 135mm. The filter size is 72mm. A dedicated petal-type hood as well
as a soft case is also part of the package.

The lens belongs to Tamron's SP (Super Performance) lineup indicating a
professional grade product. The build quality
is good indeed and a little up from the usual Tamron standard but Canon L or Tokina
AT-X lenses play in a different league. Nonetheless it feels superior to the usual
Canon consumer zooms (which is not all that difficult anyway). The control rings
operate reasonably smooth. Tamron implemented a zoom lock switch (24mm only) but
in the sample lens (a used one) the zoom mechanism was relatively stiff so zoom
creeping shouldn't be a problem anyway. Thanks to the IF (Internal Focusing)
design the front element does not rotate during zooming or focusing so using a
polarizer remains easily possible. Unfortunately the focus ring remains attached to
the AF motor so it rotates in AF mode. The Tamron AF 24-135mm SP features a
comparatively slow and quite noisy conventional AF micro motor.